1. Field of the Invention
The present invention relates to a robot controller having a function for mitigating damage to a robot when the robot is brought to an emergency stop, and for facilitating restoration of the robot from the emergency stop.
2. Description of the Related Art
In general, a robot controller brings a robot to be controlled to an emergency stop, when the robot controller detects an abnormality in the robot. In this regard, when the robot is immediately stopped, an excess load may be applied to robot, whereby the robot may be damaged.
As a relevant art document, JP 2006-012074 A discloses a program generating device for safely returning a robot to a waiting position thereof, when the robot is brought to an emergency stop due to an error, etc. The document describes that the program generating device is configured to generate a program, based on layout information of the device, information transmitted to the device, teaching points in a robot program and attribute information thereof, whereby the robot can be returned from a stopping position to a waiting position without interfering with peripheral equipment.
In the technique described JP 2006-012074 A, the robot can be safely returned to the waiting position when the robot is brought to an emergency stop due to an abnormality. However, JP 2006-012074 A does not describe means for reducing a load applied to the robot at the time of emergency stop. Further, it is necessary to previously prepare layout information of the robot and an object near the robot, and check the motion of a generated returning program.
When the robot is stopped at a position on an intricate path, etc., it may be difficult to restore the robot. On the other hand, depending on the kind of abnormality (for example, when a motor for driving the robot overheats or a torque average of the motor excessively increases), it is not necessary to immediately stop the robot and it is sufficient to stop the robot after the series of operations of the robot is completed. As such, when an abnormality, which does not require the robot to be immediately stopped, is detected, it is desired that the robot is stopped at a position where the restoration after the stoppage of the robot can be easily carried out.